Severe Weather - Monday 17th Oct

[Paul]

Thought this was worthy of a thread of it's own - we have snow for the high ground of the north, gales and heavy rain in the mix for tomorrow:

Snow:

Wind:

Rain:

We have a weather watch online:

http://www.netweathe...;type=alerthome

And the latest headline gives more detail:

http://www.netweathe...oryid=840;sess=

[Aaron]

Looks like a giant squall!

[SP1986]

The Met-office forecast for NW England was suggesting potential for a band of thundery rain moving through the region - that to me would signal a squall. Looks like it's going to be a fun day tomorrow!

[Liam J]

An intersting day coming up tomorrow thats for sure, welcome back autumn

Meto have gusts to 70mph for me Monday afternoon, although not exceptional we don't need to remind anyone that this could cause some problems in the affected areas.

Monday: Meto -

A few isolated showers at first, but spells of heavy rain developing through the afternoon, most prolonged and heaviest over Cumbria. Very windy with severe gales over coasts and hills. Maximum temperature 15 °C.

[peterf]

anyone know if our live weather vehicle is out tomorrow?

[chionomaniac]

There is a strong jet streak powering this depression. Looking at the GFS it appears that the strongest jet stream winds are set for tomorrow evening at 9pm. I would normally expect the surface winds to be strongest around this time too.

[johnholmes]

Yes, as we should expect the models, fine scale/mesh now into the time frame and the larger scale models are pretty much all singing from the same hymn sheet. The heaviest of the rain as the chart posted by Paul above, perhaps the main area of interest/concern could be SW Scotland and Cumbria; winds are generally being predicted by all the models again much as shown above, snow for the highest parts of the Scottish mountains only again as above.

In these situations with the jet its possible that things might develop a touch more overnight but it should be clear by breakfast time tomorrow if any tweaks are needed to warnings, time enough for any necessary changes to contingency plans.

[Liam J]

Further warnings now being issued, Metcheck with the latest -

Metcheck Weather Watches & Warnings

.

Issued

16 October : 08:29:32 PM

Valid Until

17 October : 09:00:32 PM

Forecasters Warning

Heavy and Persistent Rain

Areas Affected: Southwest Scotland, Northern Ireland and Northwest England

Valid: Until 21:00 Monday 17th October 2011

This is a Weather Watch issued by Metcheck at 20:29 on Sunday 16th October 2011.

A deepening Atlantic weather system pushing eastwards across northern regions of Britain and Ireland on Monday will bringing spells of persistent and heavy rain along with gale force winds.

The heaviest of the rain may give up to 2 inches (50mm) of rain over higher ground across Northern Ireland, southwest Scotland and northwest England, and very squally conditions with hail, thunder and very gusty winds may affect many areas for a short time as the cold front moves through.

In addition to this, gales or severe gales will develop over northern England during Monday afternoon, with gusts of wind of up to around 70mph likely around Irish Sea coasts.

A combination of the above conditions may bring the risk of

localised flooding along with hazardous travelling conditions

[Stormyking]

This sounds exciting, wish I was up there could get very exciting and stormy! Nice to see the snow graphics as well, winter is coming

[Backtrack]

Thought this was worthy of a thread of it's own - we have snow, gales and heavy rain in the mix for tomorrow:

Snow:

Wind:

Rain:

We have a weather watch online:

http://www.netweathe...;type=alerthome

And the latest headline gives more detail:

http://www.netweathe...oryid=840;sess=

Where can I find these charts, Paul?

[wimblettben]

This sounds exciting, wish I was up there could get very exciting and stormy! Nice to see the snow graphics as well, winter is coming

Winter isn't coming for everyone StormyKing, just for northern areas.

[AderynCoch]

What are anyone's thoughts on the possibility of a sting jet manifesting itself? I'm not an expert, but I would think that the rapid development of the shortwave combined with the alignment of the jet stream would make the formation of a sting jet more likely.

Regardless it's going to be a pretty rough day tomorrow.

[Staffordshire]

Looks good for you guys! Will this reach me down here?

[Liam J]

Current analysis chart shows the rather non-descript looking shortwave taking shape, currently 1010mb and in around 24 hours this will have bombed to around 982mb.

[wimblettben]

I think these posts are going to confuse people reading this thread guys. We need to get one thing clear.

It will be rough tomorrow for northern england and wales, but that is it.

It isn't going to be rough across the whole of the united kingdom, people should just mention these two places rather then just say it is going to be a rough day because this can get a bit misleading and confusing. Especially for the general public who doesn't know half of the more sophisticated bits.

[Staffordshire]

Sting jet?

What are anyone's thoughts on the possibility of a sting jet manifesting itself? I'm not an expert, but I would think that the rapid development of the shortwave combined with the alignment of the jet stream would make the formation of a sting jet more likely.

Regardless it's going to be a pretty rough day tomorrow.

[AderynCoch]

Sting jet?

http://en.wikipedia.org/wiki/Sting_jet

The wind speed can increase significantly with very little warning (we're talking in the 100mph ballpark). The super-strong winds in January 2005 were blamed on a sting jet: http://www.telegraph...-for-winds.html

[Paul]

A sting jet is a phenomenon which can bring very strong winds to the surface and is often associated with similar setups to what we'll be seeing tomorrow - it's fairly rare though..

http://en.wikipedia.org/wiki/Sting_jet

[chionomaniac]

I think these posts are going to confuse people reading this thread guys. We need to get one thing clear.

It will be rough tomorrow for northern england and wales, but that is it.

It isn't going to be rough across the whole of the united kingdom, people should just mention these two places rather then just say it is going to be a rough day because this can get a bit misleading and confusing. Especially for the general public who doesn't know half of the more sophisticated bits.

I haven't seen any confusing posts??

[Liam J]

As mentioned above a sting which occured during the storm of January 2005 produced wind gusts in excess of 100mph here on the Cumbrian Coast with mean speeds over 70mph recorded!!

The satellite image below is from the morning of the 2005 storm, you can see intense hook feature right over my location!

Also a very basic map showing where the very strongest winds are likely to affect tomorrow with severe gales, it will however be a windy day in many places.

[wimblettben]

I haven't seen any confusing posts??

Aren't they a little bit confusing though when they keep saying that it will be a rough day tommorow when that could mean that it will effect the whole of the UK.

They should mention the areas that are going to be effected by this event rather then not mentioning them. It's not all of the posts but it's just a few.

I am just saying because any misunderstanding will either cause a lot of dissapointment or lead to possible injury because of people not knowing where the worst of the winds will be and take action. Winds that could reach up to 70mph is a serious event.

As mentioned above a sting which occured during the storm of January 2005 produced wind gusts in excess of 100mph here on the Cumbrian Coast with mean speeds over 70mph recorded!!

The satellite image below is from the morning of the 2005 storm, you can see intense hook feature right over my location!

Also a very basic map showing where the very strongest winds are likely to affect tomorrow with severe gales, it will however be a windy day in many places.

This is the more sort of better and more precise post that I am talking about.

[Staffordshire]

Thanks for them explinations folks! Anyone recon this will be the outcome?

Just hope the wind dosent prove to much of a problem when I'm kicking for posts tommorow!

[Jane Louise]

And there's this from the UKASF chaps :

Areas Affected:

SLGT: N Isles, Highlands, W Isles, W + SW Scotland, Cumbria, Isle of Man, Northern Ireland, NW Ireland

SVR: S + E Ireland, SE Northern Ireland, SW Scotland, Borders, N England, Midlands, Wales

Synopsis:

Deepening upper low moves eastwards across the Faroes, with a surge of very cold air advected southwards on its western flank. Ahead, a thermally-active cold front provides a risk of severe weather, followed by classic coastal convective showers.

Discussion:

A very complicated frontal system develops on Monday in response to a surge of cold air on the western flank of a deep Low, steepening the thermal gradient across residual occluded fronts. This will lead to the gradual development of a cold front as it moves southeastwards across the British Isles.

Convergence and significant veering of surface wind is likely along the front. DLS >80kts and LLS >50kts, combined with >500 m^2/s^2 helicity provides a very good environment for tornadic activity, with good confidence on a squall line and embedded line convection/LEWPs.

Structural damage is a possibility from either tornadic activity or straight lined winds, with the potential for convective gusts of >70kts.

Significant moisture advection will occur along the southern side of the front, with a very notable dry punch at ~700mb. The front will be at its most active in the highlighted SVR threat region, weakening gradually as it slide southeastwards away from this area during the evening hours.

Convection will be rather shallow, however, and ELTs are too marginal to warrant a SLGT risk for lightning here. As a result, a SVR level has been issued for strong convective gusts, tornadic potential and a risk of localised flooding from prolonged torrential downpours under squall line conditions. No lightning coverage level has been issued for this event due to the shallowness of the convection.

Behind the cold front, cold mid-levels overspread the area with T500's at or below -32C. Numerous showers and a few thunderstorms are likely over coastal parts of NW Britain, continuing into the night hours, with favourable ELTs of -45C. Given the cold air aloft, some small hail is possible in some of these showers.

http://ukasf.co.uk/storm-forecasts/131

[Liam J]

And there's this from the UKASF chaps :

Areas Affected:

SLGT: N Isles, Highlands, W Isles, W + SW Scotland, Cumbria, Isle of Man, Northern Ireland, NW Ireland

SVR: S + E Ireland, SE Northern Ireland, SW Scotland, Borders, N England, Midlands, Wales

Synopsis:

Deepening upper low moves eastwards across the Faroes, with a surge of very cold air advected southwards on its western flank. Ahead, a thermally-active cold front provides a risk of severe weather, followed by classic coastal convective showers.

Discussion:

A very complicated frontal system develops on Monday in response to a surge of cold air on the western flank of a deep Low, steepening the thermal gradient across residual occluded fronts. This will lead to the gradual development of a cold front as it moves southeastwards across the British Isles.

Convergence and significant veering of surface wind is likely along the front. DLS >80kts and LLS >50kts, combined with >500 m^2/s^2 helicity provides a very good environment for tornadic activity, with good confidence on a squall line and embedded line convection/LEWPs.

Structural damage is a possibility from either tornadic activity or straight lined winds, with the potential for convective gusts of >70kts.

Significant moisture advection will occur along the southern side of the front, with a very notable dry punch at ~700mb. The front will be at its most active in the highlighted SVR threat region, weakening gradually as it slide southeastwards away from this area during the evening hours.

Convection will be rather shallow, however, and ELTs are too marginal to warrant a SLGT risk for lightning here. As a result, a SVR level has been issued for strong convective gusts, tornadic potential and a risk of localised flooding from prolonged torrential downpours under squall line conditions. No lightning coverage level has been issued for this event due to the shallowness of the convection.

Behind the cold front, cold mid-levels overspread the area with T500's at or below -32C. Numerous showers and a few thunderstorms are likely over coastal parts of NW Britain, continuing into the night hours, with favourable ELTs of -45C. Given the cold air aloft, some small hail is possible in some of these showers.

http://ukasf.co.uk/storm-forecasts/131

Thanks for posting this Jane, potential for gusts of 70knt (80mph) and even tornados, Intersting day coming up with the potential for some extreme weather coming together.

[Aaron]

The first time I have ever been under 'SVR'.